How to Read Tracks

What’s the story?

Tracking can be as shallow as reading only one track, or just following.  Another way to experience it is learning a new language by immersing one’s self in a new culture.  A visual language not taught in school, but spoken by all upon the earth, one many never notice.  This page is about learning that language.

Yes, these are all concepts of tracking and as such may also be included on other pages as Tracking Concepts.  There is an emphasis here on revealing the meaning of each concept, in a way that helps the mind assimilate it.

Every track holds a short story of its own, a set of them reveals more, and the trail takes it into the future.  At a deep level, racking is understanding the concepts and using them, a little like words or sentences, to read a story.  But, we humans with minds made for stories, who are so great with words, often miss the stories unfolding around us, to our loss.  We tend to assume there is nothing much interesting in those stories anyway …   How many see a deer, and that’s about it?

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Concept Illustrated: True Track (Canine toe pad)

The idea: Demonstrate the creation of, and difference between apparent and true track, as the track is being made.

The “true” track (term from Tom Brown, Jr.) is the track created by all surfaces of the foot in contact with the ground, up until the bottom surface of the foot itself has stopped compressing. It does not include the portions of the track created by pressure against the wall.

Another definition: “…the track bottom respective to the substrate, which was in direct contact with the track-maker’s foot (Gatesway, 2003).”: Falkingham, P.L. 2016.  Glossary: “true track…” in P.L. Falkingham, D. Marty, and A. Richter (eds.), Dinosaur Tracks: The Next Steps. Indiana University Press, Bloomington, Indiana.

Both “true” and “apparent” track are subjective terms.   The “apparent” track is often incorrectly used as the measurement of track dimensions.  The problem is that its size varies with how the foot was used, leading to inconsistent measurements.   For a useful discussion of this issue read: Falkingham, P.L. 2016.   Applying objective methods to subjective track outlines; chap. 4 in P.L. Falkingham, D. Marty, and A. Richter (eds.), Dinosaur Tracks: The Next Steps.  Indiana University Press, Bloomington, Indiana.

The “apparent” track is created during the process from the moment the foot contacts the earth … continues while weight is applied … and during the expansion of the foot outwards against the track wall … up until the last contact between foot and earth … Perhaps even a bit further.  It often includes the top of the ridge of soil pushed out and away from the foot as it rolls down onto the ground.

It can be an inaccurate measurement because it reflects the displacement of soil after the foot leaving the track has been distorted by weight and force.  It gets worse … After the foot has fully landed there can still be movement of the soil away from the edges of the foot … And the foot is still deforming and displacing soil.   Measured this way, the dimensions of the track will include some of those distortions.  These can vary with every step and are unlikely to be consistent.

Using the true track will give one a more accurate idea of actual foot size, be more consistent, and keeps everyone using the same measurements.  Variations in track measurements collected with this method are still possible, but will be reduced.

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Concept Illustrated: A Simple Tire Track and Direction of Travel

The idea: Which details in a tire track will tell you the direction that tire was being rotated by the engine?

The last part of the question is part of the answer, and the answer is definitely useful, but the greatest value lies in the benefits that come during the thought process of figuring out the answer.  In the clip below the goal is to give the observer a chance to watch one of the most obvious parts of a tire track being formed, and a start to figuring out how to answer the question.

The following version has a little more detail…

Notes about reading tire tracks for a two-wheel drive vehicle (rear-wheel drive):

– Would there be differences between tracks left by a front wheel drive, or four-wheel?

– What really goes on as the force from the engine is applied to the tires, how does that really work to move the vehicle?

– What are the last parts of the tire that can affect the track?

– So you’ve got this vehicle traveling slowly along a road (on damp-ish sand) over a ridge and down into a small valley.  Once the road reaches the valley floor it meanders for a flat-ish half-mile and then climbs up over the next ridge.  It curves a few times as it climbs that ridge.

Does it matter where along that stretch you check the tire tracks for signs of maintaining forward motion?  Any clues from the occasional small stones embedded here and there?  Are there ever times when you can see both a track left by a tire just rolling, and one created by a tire maintaining forward motion?

– What happens with all that air being shoved around as the tire rolls?

– Can you find a place in the track where a nick in the tread is repeated?  What do they give you?

– What is the tire’s footprint?  Is there any place along that vehicle’s trail where this can be seen?  Is It useful?

– How do changes in forward motion show up?

– How does inflation pressure affect the track?

– Is acceleration any different from maintaining forward motion?

– Can you see any places where they took their foot off the gas?

– How do the angles (relative to direction of travel) of the front and rear-facing edges of a tread segment affect the track?

– Do the treads on a tire interact with the substrate the same way as lugs on a Vibram shoe sole?

– If the pressure releases in the wave (in the video clip it forms below white arc) indicate force applied to maintain or alter motion, do they indicate the direction that force was applied?

– Does a tire leave the same track when moving the vehicle backwards?

– What about vehicle weight?

– How does a tire that is maintaining forward motion interact with stones it rolls over, or touches, and are there any differences between this and a tire simply coasting?

And… yes, of course there are pressure releases, but how many different kinds?

Photo of Tire Track w/inset
Photo of Tire Track w/inset

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